This invention broadly relates to a novel locking power clamp uniquely designed for use in holding a door of a container in a closed position. More specifically, the invention relates to a special new locking power clamp suitable for use with industrial vacuum loader trucks, wherein a clamping system is required to hold the rear door of the vacuum loader in a tightly closed and sealed position.
There has been a problem involved with prior industrial vacuum loader trucks which utilize a large (sometimes circular) door at the rear of the vacuum loader, with the door being held in a closed position when the vacuum system of the truck is being utilized. The rear doors on these vacuum loaders are provided with a peripheral sealing member such as a rubber or elastomeric peripheral seal, which seals the door into a generally airtight position when the door is closed. Previous clamping systems used to hold the door in a closed position have been unsatisfactory, such as for example, due to the fact that they exert uneven clamping loads on the seal, which in many instances causes the seal to be unevenly applied. In addition, the previous clamping mechanisms did not provide easy on-off positioning, such that when it was desired to open the rear door of the vacuum loader truck the clamping system could be easily and economically withdrawn from the periphery of the door; and then, vice-versa, easily and rapidly put back into a closed clamping position following closure of the door mechanism.
The state-of-the-art in this area is generally shown by commonly assigned co-pending U.S. patent application Ser. No. 08/916065 filed Aug. 21, 1997; and, by earlier U.S. Pat. No. 5,287,602 issued Feb. 22, 1994 and entitled xe2x80x9cPowered Toggle Latch.xe2x80x9d
Briefly stated, the present invention consists of a new locking power clamp assembly for repetitive use in uniformly and securely clamping a closure member over a container opening, said clamp assembly comprising: a clamp arm member having a clamping contact surface thereon, said clamp arm member being of elongated dimension and being capable of generally rotational movement, such that when the clamp assembly is opened, the clamp arm member will move in a generally perpendicular direction away from the plane of the closure member and also will move in a radial direction away from a peripheral edge of the closure member, at least one frame member, at least two link arm members, each being of different length, a fluid operated piston and cylinder assembly, with the piston being connected to one of the link arm members, and the cylinder being connected to said frame member, a rotator member secured to the frame member to support and assist proper movement of the clamp arm member.